Preparation of disperse bisanil dyes derived from diaminomaleonitrile

ABSTRACT

Extremely bright, tinctorially strong disperse dyes derived from diaminomaleonitrile and selected aromatic and heterocyclic aldehydes, and their preparation, useful for dyeing and printing polyester and polyester-cotton blend fibers in yellow to blue shades of generally good fastness properties, which dyes are of the general formula 
     
         Ar.sub.1 --CH=N--C(CN)=C(CN)--N=CH--Ar.sub.2 
    
     wherein Ar 1  and Ar 2  are aromatic or aromatic-like groups, for example, phenyl or pyridyl.

CROSS-REFERENCE TO RELATED APPLICATION

This is a division of application Ser. No. 430,414 filed Jan. 3, 1974now U.S. Pat. No. 3,914,276.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to yellow to blue bisanil disperse dyes preparedfrom diaminomaleonitrile.

2. Description of the Prior Art

Monocondensation products of diaminomaleonitrile with various aldehydesare known in the art. Onoda in Nippon Nogeikagaku Kaishi, 36 (2), 167-72(1962) discloses yellow monocondensation products of diaminomaleonitrilewith aldehydes; the products are of the formula

    Ar--CH=N--C(CN)=C(CN)--NH.sub.2

wherein Ar is either phenyl, p-dimethylaminophenyl or furfuryl.Robertson and Vaughan in J. Am. Chem. Soc., 80, 2691 (1958) discloseyellow monocondensation products of such formula wherein Ar is eitherp-hydroxyphenyl, p-nitrophenyl or cinnamyl. Reported attempts tointroduce a second mole of the same aldehyde appear to have beenunsuccessful and attempts to introduce a second mole of a differentaldehyde with the monoanil (Schiff base) resulted in displacement of thealdehyde residue of the original derivative. Such displacement facilelyoccurred when the second aldehyde possessed a carbonyl carbon atom ofgreater electron deficiency than the original aldehyde; for example,p-nitrobenzaldehyde > benzaldehyde > p-hydroxybenzaldehyde (decreasingorder of facility of displacement). Hinkel et al. in J. Chem. Soc., 1432(1937) disclose yellow monocondensation products of such formula whereinAr is either phenyl, p-anisyl, salicyl or m-bromosalicyl. None of theaforementioned references discloses that the monoadducts ofdiaminomaleonitrile and aldehydes are useful as dyestuffs for syntheticfibers, especially polyester fibers.

U.S. Pat. No. 2,200,689 discloses heterocyclic pyrazinocyanine pigmentdyestuffs which are obtainable by condensing diaminomaleonitrile with1,2-dicarbonyl compounds, such as diacetyl, glyoxal, benzil,ortho-benzoquinone, acenaphthenequinones, thionaphthenequinones,phenanthrenequinones and aceanthrenequinones, at about 100°-300°C. inthe presence of a solvent, pyridine and a metal salt. They are describedas having good fastness properties.

Linstead et al. in J. Chem. Soc., 911 (1937) describe a variety ofphthalocyanine-type pigments which vary in color from blue to green withincreasing molecular weight; they are prepared by treatment of2,3-dicyanopyrazines of the formula ##SPC1##

Wherein R is H, CH₃ or phenyl with copper salts. The2,3-dicyanopyrazines can be prepared by condensation ofdiaminomaleonitrile with, respectively, glyoxal, diacetyl and benzil.

OBJECTS AND SUMMARY OF THE INVENTION

The dye trade is continuously seeking new and better dyes for use inexisting and newly developed dyeing and printing systems and for usewith fibers, blended fibers and fabrics, which fabrics may, for example,be subjected to an after-treatment (after-dyeing) step, such as theapplication of a permanent press resin composition, to impart aparticularly desirable property to the dyed fabric. Dyes which combinebrightness of shade and high tinctorial strength with good applicationand fastness properties are particularly useful in such systems. Brightdyes are more attractive than dull dyes and offer greater versatility informulating mixed shades. Commercial disperse dyes for use on polyesterand other synthetic and semi-synthetic fibers tend as a class to haverather dull shades. Bright disperse dyes often suffer from poorlightfastness or high cost, or both.

It is an object of this invention to provide yellow to blue dispersedyes. It is a further object to provide dyes which exhibit outstandingbrightness of shade and high tinctorial strength and which are generallyfluorescent and significantly brighter than known existing dispersedyes. It is a still further object to provide disperse dyes withacceptable fastness to light and sublimation on polyester andpolyester-cellulosic blend fibers. Yet another object is to provideeconomically attractive dyes derived from inexpensive startingmaterials. A further object is to provide a variety of processes forpreparing such dyes.

In summary, this invention relates to bisanil disperse dyes (and theirpreparation) of the formula Ar₁ --CH=N--C(CN)=C(CN)--N=CH-Ar₂ whereineach of Ar₁ and Ar₂ is independently selected from

1. benzo(5- and 6-membered)heterocyclic groups containing 0-4 methylsubstituents and

2. phenyl, naphthyl, 5-membered heterocyclic and 6-membered heterocyclicgroups containing 0-3 substituents selected from NO₂, halogen, CN, C₁₋₄alkyl, C₁₋₄ alkoxy, OCH₂ -phenyl, phenyl, CF₃, OH, OC₁₋₄ alkylene-N(C₁₋₄alkyl)₂, C₂₋₄ alkylene-Cl, NHCONH₂, NHCOA, NHSO₂ A, SR₈, SO₂ R₈, NHR₁,NHCOC₁₋₄ alkylene-B and -NR₁ R₂ wherein:

a. R₁ is C₁₋₄ alkyl or C₂₋₄ alkylene-R₃ ;

b. R₂ is C₁₋₄ alkyl, C₂₋₄ alkylene R₄ or, if Ar₁ or Ar₂ is phenyl, C₃alkylene attached to a phenyl position which is ortho to the position towhich the nitrogen is attached;

c. R₃ is CN, halogen, OH, phenyl, C₁₋₄ alkoxy, OC₁₋₄ alkylene-CN, CO₂ A,OCOA, OCONHA or CO₂ C₁₋₄ alkylene-OCOA;

d. R₄ is CN, halogen, OH, phenyl, OC₁₋₄ alkylene-CN, CO₂ A, OCOA, CO₂C₁₋₄ alkylene-OCOA, SO₂ A, phthalimido, succinimido, glutarimido,OCOCH=CH₂, CH₂ --CH(OCOA)CH₂ OA or CH₂ CH(OCONHA)CH₂ OA;

e. A is C₁₋₄ alkyl or R₅ ;

f. B is halogen, C₁₋₄ alkoxy or R₅ ;

g. R₅ is phenyl containing 0-2 substituents selected from C₁₋₄ alkyl,C₁₋₄ alkoxy, halogen, NO₂, CN, C₁₋₄ alkylCONH and NR₆ R₇ wherein each ofR₆ and R₇ is independently selected from H and C₁₋₄ alkyl, with at leastone of R₆ and R₇ being C₁₋₄ alkyl; and

h. R₈ is C₁₋₄ alkyl, C₂ H₄ OH, C₅₋₆ cycloalkyl or R₅.

DETAILED DESCRIPTION OF THE INVENTION

The bisanil dyes of the above formula can exist in two isomeric forms,the cis arrangement ##EQU1## and the trans arrangement ##EQU2##Furthermore, the dyes can be symmetrical (if Ar₁ and Ar₂ are identical)or unsymmetrical (if Ar₁ and Ar₂ are different). The dyes can beprepared by condensing diaminomaleonitrile with the aldehydes Ar₁ CHOand Ar₂ CHO as hereinafter described, Ar₁ CHO and Ar₂ CHO being the sameor different. The present invention also relates to additional processesfor preparing the heretofore defined symmetrical and unsymmetrical, cis-and trans-bisanil dyes.

Diaminomaleonitrile is generally referred to as HCN tetramer since it isavailable in low yields from the base catalyzed tetramerization of HCNas shown in U.S. Pat. No. 2,499,441. Tetramerization of HCN todiaminomaleonitrile also occurs in the presence of a catalytic amount ofa basic catalyst and at least one of the cocatalystsdiiminosuccinonitrile or cyanogen as shown in U.S. Pat. No. 3,629,318.Tetramerization of HCN in an aprotic solvent, such as dimethylsulfoxide,in the presence of a catalyst, such as sodium cyanide, at 60°-70°C. atatmospheric pressure, as shown in U.S. Pat. No. 3,704,797, provides yetanother route to diaminomaleonitrile; such a procedure also is describedin Chemical Week, July 12, 1972, page 36 and in European Chemical News,March 2, 1973, page 20. Diaminomaleonitrile also can be prepared fromdiiminosuccinonitrile which itself is preparable, according to J. Org.Chem., 37, 4133 (1972), in high yield by the base catalyzed addition ofHCN to cyanogen. Diiminosuccinonitrile can be converted by chemicalreagents to diaminomaleonitrile, for example, by reaction thereof withHCN as shown in U.S. Pat. No. 3,564,039. Diaminomaleonitrile also can beprepared by reaction of diiminosuccinonitrile with hydrogen in thepresence of a Group VIII transition metal hydrogenation catalyst asshown in U.S. Pat. No. 3,551,473.

The yellow to blue unsymmetrical bisanil disperse dyes can be preparedby condensing 1 mole of diaminomaleonitrile with 1 mole each ofdifferent aryl aldehydes Ar₁ CHO and Ar₂ CHO. Symmetrical bisanil dyescan be prepared by condensing 1 mole of diaminomaleonitrile with 2 molesof a single aryl aldehyde.

Examples of aryl aldehydes, Ar₁ CHO and/or Ar₂ CHO, which are useful inthe preparation of the bisanil dyes are given in Table I.

TABLE I

4-[n,n-bis(methyl)amino]benzaldehyde

4-bromo-2,5-diisopropylbenzaldehyde

4-[N,N-bis(n-propyl)amino]-2-methylbenzaldehyde

6-formyl-N-(methyl)-2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline

5-bromothiophene-2-carboxaldehyde

4'-[N-ethyl-N-(2-methoxycarbonylethyl)amino]-2-methylbenzaldehyde

4'-[N-(2-butoxycarbonylethyl)-N-ethylamino]-2'-methylbenzaldehyde

4-ethylcarbonylamidobenzaldehyde

N-methylindole-3-carboxaldehyde

4-thiomethoxybenzaldehyde

4-thio-n-butoxybenzaldehyde

4-thiomethoxynaphthaldehyde

4-phenylsulfonylbenzaldehyde

4-methylsulfonylbenzaldehyde

4-thio-(2'-hydroxyethoxy)benzaldehyde benzaldehyde

4-(N-cyanoethyl-N-methylamino)benzaldehyde

4-chlorobenzaldehyde

2,6-dichlorobenzaldehyde

2-nitrobenzaldehyde

3-nitrobenzaldehyde

4-nitrobenzaldehyde

4-[N,N-bis(ethyl)amino]benzaldehyde

4-[N,N-bis(ethyl)amino]-2-hydroxybenzaldehyde

3-hydroxybenzaldehyde

2-hydroxybenzaldehyde

4-hydroxybenzaldehyde

4-[N-cyanoethyl-N-ethylamino]-2-methylbenzaldehyde

4-[N,N-bis(hydroxyethyl)amino]benzaldehyde

4-[N,N-bis(cyanoethyl)amino]benzaldehyde

4-[N,N-bis(n-propyl)amino]benzaldehyde

3-chloro-4-hydroxy-5-methoxybenzaldehyde

4-chloro-3-nitrobenzaldehyde

5-chloro-2-nitrobenzaldehyde

3,4-dibenzyloxybenzaldehyde

3,5-dibromosalicylaldehyde

3,5-di-tert.-butyl-4-hydroxybenzaldehyde

4'-[2-(diethylamino)-ethoxy]benzaldehyde

2,5-dihydroxybenzaldehyde

3,4-dihydroxybenzaldehyde

2,3-dimethyl-4-methoxybenzaldehyde

2,5-dimethyl-4-methoxybenzaldehyde

2,4-dimethylbenzaldehyde

2,5-dimethylbenzaldehyde

2-ethoxybenzaldehyde

4-ethoxybenzaldehyde

3-ethoxy-4-hydroxybenzaldehyde

4-cyanobenzaldehyde

4-acetamidobenzaldehyde

2-methoxybenzaldehyde

3-methoxybenzaldehyde

3-benzyloxybenzaldehyde

4-benzyloxybenzaldehyde

4-biphenylcarboxaldehyde

5-bromo-2-methoxybenzaldehyde

2-bromobenzaldehyde

3-bromobenzaldehyde

5-bromosalicylaldehyde

5-bromovanillin[5-bromo-4-hydroxy-3-methoxybenzaldehyde]

5-bromo-3,4-dimethoxybenzaldehyde

6-bromo-3,4-dimethoxybenzaldehyde

2'-(2-chloroethyl)benzaldehyde

2-chloro-6-fluorobenzaldehyde

4-ethoxy-3-methoxybenzaldehyde

3-ethoxysalicylaldehyde

3-fluoro-4-methoxybenzaldehyde

3-fluorobenzaldehyde

4-fluorobenzaldehyde

3-hydroxy-4-methoxybenzaldehyde

2-hydroxy-4-methoxybenzaldehyde

2-hydroxy-5-methoxybenzaldehyde

4-hydroxy-3-methoxybenzaldehyde (vanillin)

2-hydroxy-1-naphthaldehyde

3-hydroxy-4-nitrobenzaldehyde

4-hydroxy-3-nitrobenzaldehyde

5-hydroxy-2-nitrobenzaldehyde

2,4,6-trimethylbenzaldehyde (mesitaldehyde)

2-methoxy-1-naphthaldehyde

4-methoxy-1-naphthaldehyde

3-methyl-4-methoxybenzaldehyde

4-hydroxy-3-methoxy-5-nitrobenzaldehyde (5-nitrovanillin)

3,4-dimethoxy-6-nitrobenzaldehyde

2-methylbenzaldehyde

3-methylbenzaldehyde

4-methylbenzaldehyde

2,4,6-triethoxybenzaldehyde

2,3,4-trimethoxybenzaldehyde

2,4,5-trimethoxybenzaldehyde

2,4,6-trimethoxybenzaldehyde

3,4,5-trimethoxybenzaldehyde

5-bromothiophene-2-carboxaldehyde

2-furaldehyde

5-methoxyindole-3-carboxaldehyde

5-methyl-2-furaldehyde

5-methylindole-3-carboxaldehyde

6-methyl-2-pyridinecarboxaldehyde

N-methylpyrrole-2-carboxaldehyde

3-methyl-2-thiophenecarboxaldehyde

5-methyl-2-thiophenecarboxaldehyde

2-pyridinecarboxaldehyde

3-pyridinecarboxaldehyde

4-pyridinecarboxaldehyde

pyrrole-2-carboxaldehyde

3,5-dichlorobenzaldehyde

2,4-dichlorobenzaldehyde

3,4-dichlorobenzaldehyde

4-[N,N-bis(ethyl)amino]-2-methylbenzaldehyde

2-chloro-5-nitrobenzaldehyde

2-chloro-6-nitrobenzaldehyde

2,4-dinitrobenzaldehyde

2,6-dinitrobenzaldehyde

2-acetamido-4-[N,N-bis(ethyl)amino]benzaldehyde

2-acetamido-4-[N,N-bis(ethyl)amino]-5-methoxybenzaldehyde

2-benzamido-4-[N,N-bis(ethyl)amino]benzaldehyde

3-cyanobenzaldehyde

indole-3-carboxaldehyde

thiophene-2-carboxaldehyde

quinoline-2-carboxaldehyde

4'-[N-(2-acetoxy-3-phenoxypropyl)-N-ethylamino]-2'-methylbenzaldehyde

4'-[N-(2-benzoyloxy-3-phenoxypropyl)-N-ethylamino]-2'-methylbenzaldehyde

2,5-dimethoxybenzaldehyde

2,4-dimethoxybenzaldehyde

3,4-dimethoxybenzaldehyde

2-fluorobenzaldehyde

3,5-dimethoxybenzaldehyde

2-trifluoromethylbenzaldehyde

4-[N-cyanoethyl-N-n-propylamino]benzaldehyde

4-[N,N-bis(isopropyl)amino]benzaldehyde

4-[N,N-bis(n-butyl)amino]benzaldehyde

4-[N,N-bis(n-butyl)amino]-2-methylbenzaldehyde

1-naphthaldehyde

2-naphthaldehyde

4-bromobenzaldehyde

4-[N,N-bis(methyl)amino]naphthaldehyde

4-[N,N-bis-(ethyl)amino]naphthaldehyde

4-[N-cyanoethyl-N-ethylamino]naphthaldehyde

4-[N-ethylamino]naphthaldehyde

4'-[N-ethyl-N-(2-phenylcarbamoyloxy-3-phenoxypropyl)amino]-2'-methylbenzaldehyde

4-[N-benzoyloxyethyl-N-ethylamino]benzaldehyde

4-[N-benzoyloxyethyl-N-cyanoethylamino]benzaldehyde

4-[N-cyanoethyl-N-propionyloxyethylamino]benzaldehyde

4-methoxybenzaldehyde

3-chlorobenzaldehyde

2-chlorobenzaldehyde

4-[N-cyanoethyl-N-ethylamino]benzaldehyde

2-chloro-4-[N,N-bis(ethyl)amino]benzaldehyde

2-chloro-4-[N,N-bis(methyl)amino]benzaldehyde

4'-[N,N-bis(2-chloroethyl)amino]benzaldehyde

4'-[N,N-bis(2-acetoxyethyl)amino]benzaldehyde

4'-[N,N-bis(2-acetoxyethyl)amino]-2'-benzamidobenzaldehyde

4'-[N,N-bis(2-butyroxyethyl)amino]benzaldehyde

4'-[N,N-bis(2-acetoxyethyl)amino]-2'-acetamidobenzaldehyde

4-[N-cyanoethyl-N-hydroxyethylamino]benzaldehyde

4-[N-cyanoethyl-N-phenethylamino]benzaldehyde

4'-[N,N-bis(2-valerylethyl)amino]benzaldehyde

4'-[N-cyanoethyl-N-(2-phenoxycarbonylethyl)amino]benzaldehyde

4'-[N-(2-acrylyloxyethyl)-N-cyanoethylamino]benzaldehyde

4'-[N-(2-butoxycarbonylethylamino]-2'-chlorobenzaldehyde

4'-[N-(2-methoxycarbonylethyl)amino]naphthaldehyde

4'-[N-(2-butoxycarbonylethyl)amino]naphthaldehyde

4-[N,N-bis(ethyl)amino]-2-ureidobenzaldehyde

4'-[N-benzyl-N-(3-cyanopropyl)amino]-2'-ureidobenzaldehyde

4'-{N-[2-(3-dimethylaminophenoxycarbonyl)ethyl]-N-ethylamino}benzaldehyde

4'-}N-[2-(3,5-dichlorophenoxycarbonyl)ethyl]amino}-benzaldehyde

2'-acetamido-4'-{N-[2-(4-methoxyphenoxycarbonyl)ethyl]amino}benzaldehyde

4'-{N-[2-methyl-4-methoxyphenoxycarbonyl)ethyl]N-methylamino}benzaldehyde

4'-{N-[2-(2-chlorobenzoyloxy)ethyl]-N-methylamino}benzaldehyde

4'-{N-ethyl-N-[2-(4- nitrobenzoyloxy)ethyl]amino}benzaldehyde

4'-{N-[2-(4-acetamidobenzoyloxy)ethyl]amino}benzaldehyde

2'-acetamido-4'-{N-[2-(2-chloro-4-nitrobenzoyloxy)ethyl]-N-ethylamino}benzaldehyde

4'-{N-[3-(4-bromobenzoyloxy)propyl]amino}benzaldehyde

4'-{N-[2-(2-methyl-3-nitrobenzoyloxyethoxycarbonyl)ethyl]amino}benzaldehyde

4'-{N-[2-(4-methoxybenzoyloxyethoxycarbonyl)propyl]amino}benzaldehyde

4'-{N-[2-(3-cyanobenzoyloxyethoxycarbonyl)ethyl]amino}benzaldehyde

4'-{N-[2-(2-methylbenzoyloxyethoxycarbonyl)ethyl]amino}benzaldehyde

2'-chloro-4'-{N-[2-(propionyloxyethoxycarbonyl)ethyl]amino}benzaldehyde

4'-{N,N-bis[2-(butyryloxyethoxycarbonyl)ethyl]amino}benzaldehyde

4'-{N[2-(benzoyloxyethoxycarbonyl)ethyl]-N-methylamino}benzaldehyde

4-(N-cyanoethylamino)-3-n-butylbenzaldehyde

4'-[N,N-bis(ethyl)amino]-2'-(3-methoxypropionamido)benzaldehyde

2-acetamido-4-(N-cyanoethyl-N-ethylamino)benzaldehyde

2'-butyramido-4'-[N-cyanoethyl-N-(2-methyloxycarbonylethyl)amino]benzaldehyde

2'-(3-chloropropionamido)-4'-[N-phenethyl-N-n-propylamino]benzaldehyde

2'-acetamido-4'-[N-(2-methoxycarbonylethyl)amino]-5'-methoxybenzaldehyde

4'-[N,N-bis(ethyl)amino]-5'-methoxy-2'-(3-methylbenzamido)benzaldehyde

2'-chloroacetamido-4'-[N,N-bis(ethyl)amino]-5'-methoxybenzaldehyde

2'-(3-chlorobutyramido)-4'-[N,N-bis(cyanoethyl)amino]-5'-methoxybenzaldehyde

2'-acetamido-4'-[N,N-bis(2-acetoxyethoxycarbonylethyl)amino]-5'-methoxybenzaldehyde

4'-[N,N-bis(2-acetoxyethyl)amino]-2'-(2-chlorobenzamido)-5'-methoxybenzaldehyde

2'-acetamido-4'-[N-(2-acetoxyethyl)-N-cyanoethylamino]-5'-methoxybenzaldehyde

4'-[N-cyanoethyl-N-ethylamino]-5'-methoxy-2'-(4-nitrobenzamido)benzaldehyde

4'-[N-(2-methoxycarbonylethyl)-N-methylamino]benzaldehyde

4'-[N,N-bis(2-acetoxyethyl)amino]-2'-methylsulfonamidobenzaldehyde

4'-[N-(2-acetoxyethyl)-N-cyanoethylamino]-2'-phenylsulfonamidobenzaldehyde

4'-[N,N-bis(2-acetoxyethyl)amino]-5'-methoxy-2'-methylsulfonamidobenzaldehyde

4'-[N-ethyl-N-(2-succinimidoethyl)amino]-2'-methylbenzaldehyde

4'-[N-ethyl-N-(2-phthalimidoethyl)amino]-2'-methylbenazldehyde

4'-[N-cyanoethyl-N-(2-succinimidoethyl)amino]-2'-methylbenzaldehyde

4'-[N-ethyl-N-(2-glutarimidoethyl)amino]-2'-methylbenzaldehyde

6-formyl-N-(β-phenylcarbamoyloxyethyl)-2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline

6-formyl-N-cyanoethyl-2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline

6-formyl-N-(β-acetoxyethyl)-2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline

6-formyl-N-(β-benzoyloxyethyl)-2,2,4,7-tetramethyl-1,2,3,4-tetrahydroquinoline

4'-[N,N-bis(2-cyanoethylethoxyethyl)amino]-2'-methylbenzaldehyde

2'-acetamido-4'-[N-(2-cyanoethylethoxyethyl)-N-ethylamino]benzaldehyde

4'-[N-ethyl-N-(2-methylsulfonylethyl)amino]-2'-methylbenzaldehyde

4'-[N-cyanoethyl-N-(2-phenylsulfonylethyl)amino]benzaldehyde

4'-[N-cyanoethyl-N-(2-methoxyethylamino]benzaldehyde

4'-[N-ethyl-N-(2-propionoxyethyl)amino]-2'-methylbenzaldehyde

indole-2-carboxaldehyde

N-ethylindole-3-carboxaldehyde

N-(2-acetoxyethyl)indole-3-carboxaldehyde

thianaphthene-2-carboxaldehyde

thianaphthene-3-carboxaldehyde

4,5-dibromothiophene-2-carboxaldehyde

4-bromothiophene-2-carboxaldehyde

thiophene-3-carboxaldehyde

5-[N,N-bis(ethyl)amino]indole-3-carboxaldehyde

5-[N,N-bis(ethyl)amino]thiophene-2-carboxaldehyde

5-[N,N-bis(methyl)amino]-1,3,4-thiadiazole-2-carboxaldehyde

5-[N,N-bis(ethyl)amino]-1,4-thiazole-2-carboxaldehyde

4-bromofuran-2-carboxaldehyde

pyridine-N-oxide-3-carboxaldehyde

The aldehydes listed above are either commercially available or can beprepared by well known prior art procedures, such as the Vilsmeierreaction using dimethylformamide, phosphorus oxychloride and theappropriate substitued aryl compound.

Further to the above, the aryl aldehydes can be modified by theincorporation of sulfonic acid groups (SO₃ H) to provide, when condensedwith diaminomaleonitrile as described herein, acid dyes for potentialuse on nylon. Similarly, incorporation of basic groups (-N⁺(alkyl)₃)canprovide cationic dyes having potential utility on polyacrylonitrile andacid-modified polyester and polyamide fibers.

The symmetrical dyes, that is, bisanil dyes of the above formula whereinAr₁ and Ar₂ are the same, can be prepared in one step by condensing 1mole of diaminomaleonitrile with 2 moles of an aryl aldehyde, in thepresence of an acidic catalyst, in an organic solvent, at 50°-150°C.,while continuously removing the water formed during the reaction eitherby azeotropic distillation or by the action of a dehydrating agent, suchas phosphorus pentoxide or dicyclohexylcarbodiimide. Preferred catalystsin the condensation includes sulfuric acid, polyphosphoric acid andp-toluenesulfonic acid. Organic solvents, such as acetonitrile,tetrahydrofuran, dimethylformamide, hexamethylphosphoramide,dimethylacetamide, toluene, xylene, benzene and monochlorobenzene areequally useful. After cooling the reaction mixture to room temperature,the precipitated bisanil dyestuff can be isolated by filtration

It has been discovered that condensation of 2 moles of4-[N,N-bis(ethyl)amino]benzaldehyde and 1 mole of diaminomaleonitrile at50°-55°C. in hexamethylphosphoramide containing sulfuric acid ascatalyst, in the presence of phosphorus pentoxide to remove the water orreaction, over a 6 hour period, provides the bright, fluorescent, redcis-bisanil dyeN,N'-{4-[N,N-bis(ethyl)amino]benzylidene}diaminomaleonitrile having thestructure ##SPC2##

The cis geometry about the central carbon-carbon double bond isevidenced by the large observed dipole moment (14.6 D) of this dye. Thisresult correlates well with the large dipole moment (7.8 D) ofdiaminomaleonitrile as reported by Webb et al. in J. Am. Chem. Soc., 77,3491-3 (1955). Depending on the rotation of the amino groups, a muchlower dipole moment is predicted for the trans configuration. Ingeneral, the cis-symmetrical bisanil dyes prepared by the aforementionedprocess undergo isomerization and/or partial hydrolysis upon attemptedrecrystallization from dimethylformamide, acetonitrile or nitromethane,yielding mixtures of the cis- and trans-symmetrical bisanils and theyellow monoanil species.

A useful one-step process for the preparation of symmetrical bisanildyes involves the condensation of at least about 2 moles of arylaldehyde with 1 mole of diaminomaleonitrile in glacial acetic acid, atabout the boiling temperature of the acid, for extended periods of time.This process provides the thermodynamically more stable trans isomerhaving the structure ##SPC3##

The low dipole moment of 3.2D on this product supports the structureassignment. Reaction times of up to about 4 hours at 115°-120°C.generally are adequate for obtaining substantially trans isomer. Uponcooling to room temperature, the trans-bisanil crystallizes and can beisolated from the acid medium. Yields of 60-75% of high puritysymmetrical trans-bisanils can be obtained by this procedure. A similarresult can be obtained by condensing 1 mole of the monoanil ofdiaminomaleonitrile with 1 mole of an aryl aldehyde under similarconditions to those described above.

The unsymmetrical bisanil dyes, that is, bisanil dyes prepared fromdiaminomaleonitrile and two different aldehydes, can be prepared instepwise fashion by monocondensation of 1 mole of a first aryl aldehydewith 1 mole of diaminomaleonitrile to provide the yellow monoanilderivative. The monocondensation is preferably run in an organicsolvent, such as tetrahydrofuran, acetonitrile or benzene, for up toabout 4 hours, at the boiling point of the solvent, in the presence ofan acid catalyst, such as sulfuric acid. The resultant yellow monoanil(1 mole) is then treated with 2 moles of a different aryl aldehyde in anorganic solvent in the presence of a secondary or tertiary aminecatalyst, while azeotropically removing the water formed in thecondensation. Preferred amine catalysts are piperidine andtriethylenediamine. No condensation occurs in the absence of catalyst.Useful organic solvents include monochlorobenzene, acetonitrile,dimethylformamide, isopropanol, dichloroethane, toluene and benzene, thelatter being most useful. By way of example of the stepwise condensationdiaminomaleonitrile (1 mole) is condensed with4-[N,N-bis(ethyl)amino]benzaldehyde (1 mole) in tetrahydrofuran, in thepresence of sulfuric acid, at 60°-65°C., for 3 hours; a high yield, forexample, 80-90%, of the yellow monoanilN-{4-[N,N-bis(ethyl)amino]benzylidine}diaminomaleonitrile is obtained.This intermediate monoanil possesses inherent deficiencies inapplication properties on polyester when compared to the bisanil. Themonoanils, in general, also do not exhibit the fluorescence andbrightness which are characteristic of the bisanil derivatives ofdiaminomaleonitrile. Subsequent condensation of the aforesaid monoanil(1 mole) with 2 moles of 4-chlorobenzaldehyde in benzene, in thepresence of a catalytic amount of piperidine, at 75°-80°C., whilecontinuously azeotroping water over a 6-hour period, provides, afterremoval of solvent, a 40-50% yield of the trans-unsymmetrical bisanilN-{4-[N,N-bis(ethyl)amino]benzylidene}-N'-(4-chlorobenzylidene)diaminomaleonitrilehaving the structure ##SPC4##

When the amount of basic catalyst is less than 0.50 mole per mole ofmonoanil, the trans-unsymmetrical dye is contaminated with thecis-unsymmetrical dye and both the cis and trans forms of thesymmetrical adductN,N'-{4-[N,N-bis(ethyl)amino]benzylidene}diaminomaleonitrile. The latterderivative is believed to be formed by initial hydrolysis ofN-{4-[N,N-bis(ethyl)amino]benzylidene}-N'-(4-chlorobenzylidene)diaminomaleonitrileto N-(4-chlorobenzylidene)diaminomaleonitrile and4-diethylaminobenzaldehyde, followed by subsequent reaction of thelatter aldehyde with the starting monoanilN-{4-[N,N-bis(ethyl)amino]benzylidene}diaminomaleonitrile. The ratio ofcis and trans products obtained does not change with longer reactiontimes, for example, up to about 18 hours. However, when the condensationis carried out with an increased amount of basic catalyst, for example,0.50 mole of catalyst to one mole of monoanil, only thetrans-symmetrical and trans-unsymmetrical bisanils are formed. Usinglarger amounts of aryl aldehyde, for example, greater than 2 moles permole of monoanil, or using other solvents does not substantially alterthe product.

The major drawback of the above-described two-step process for preparingunsymmetrical bisanils of diaminomaleonitrile is that, under thereaction conditions, the product mixtures contain both symmetrical andunsymmetrical dyes. Due to the plurality of products capable of beingformed by this process, the trans-unsymmetrical dyes are generallyobtained only in moderate yields and complex separation methods usuallyare necessary to effect satisfactory resolution of the product mixtures.An improved process (a preferred process herein) for the preparation oftrans-unsymmetrical bisanil adducts of diaminomaleonitrile (thepreferred adducts herein) is illustrated by the following generalscheme: ##EQU3## This four-step synthesis involves an initialcondensation of 1 mole of diaminomaleonitrile with a first aryl aldehydeto give the monoanil adduct. In practice, any organic solvent can beused in this initial step, ketones and aldehydes which can react withdiaminomaleonitrile being an exception. It is not necessary to have thediaminomaleonitrile in solution. Solvents which can be used in thiscondensation include tetrahydrofuran, ethyl "Cellosolve",dimethylformamide, methanol, ethanol and mixtures thereof. A usefultemperature range is 20°-80°C.; however, a temperature of 25°-30°C. ispreferred and provides the best yield and quality of product. Reactiontimes of about 4-17 hours can be employed. Acid catalysts, such assulfuric acid, hydrochloric acid, p-toluenesulfonic acid andtrifluoroacetic acid, can be used. The monoanil can either be isolatedor the reaction mixture containing same can be used in the next step.

Reduction of the monoanil, for example, with sodium borohydride, givesthe N-benzyldiaminomaleonitrile derivative in high yield. Reduction ofthe monoanil adduct is a critical feature of the improved process inthat it precludes the formation of undesirable mixtures during thesubsequent condensation with Ar₂ CHO (as was the case with theabovedescribed two-step process). Preferably, an organic solvent ispresent during the reduction step; included among the preferred solventsare tetrahydrofuran, methanol, ethanol and ethyl "Cellosolve", thelatter being especially preferred. The addition of sodium borohydrideprovides an exothermic reaction and external cooling is necessary tokeep the reaction temperature within the preferred 10°-35°C. range.Above 35°C. the product obtained is of poor quality. The sodiumborohydride normally can be added over a 20-40 minute period while stillmaintaining the temperature below 35°C. Other reducing agents, such aslithium aluminum hydride and lithium borohydride, can also be used. Theamount of reducing agent should be at least 0.50 mole per mole ofmonoanil to obtain complete reduction. The reduced monoadduct can beused without further purification in the next step of the reactionsequence. The reduction works best when at least some alcoholic solventis present in the reaction mixture. Thus, the initial condensation ofdiaminomaleonitrile with Ar₁ CHO in tetrahydrofuran (THF) to give themonoanil, as previously described, followed by addition of methanol tothe THF reaction mass and reduction of the monoanil with sodiumborohydride, provides high yields of reduced monoadduct. In addition, bycarrying out the initial condensation reaction at 25°-30°C. rather thanat or above the boiling point of tetrahydrofuran (65°-66°C.), forexample, at 80°C., and by keeping the subsequent reduction temperaturebelow 25°C., excellent yields, for example, greater than 90% of theory,of the reduced monoadduct can be obtained.

Condensation of 1 mole of the reduced monoadduct with 1 mole of a secondaryl aldehyde Ar₂ CHO provides the monoreduced bisadduct. This step canbe carried out with the same solvents and acidic catalysts used in theinitial monocondensation step. However, best results are obtained when asolvent such as methanol or ethanol is used. In such a solvent themonoreduced bisadduct is very insoluble and precipitates as formed. Room(ambient) temperature (25°-30°C.) is preferred in this step formaximizing purity of product; higher temperatures cause the product todarken considerably.

In order to obtain bisanil dyes having a red shade it is necessary, inmany cases, to have a dialkylamino group on at least one of the aromaticrings. It is preferred to add the appropriate dialkylaminobenzaldehydeas the second aryl aldehyde rather than as the first aryl aldehyde sincethe monoanil formed from such an aldehyde is, in some cases, not reducedcleanly by sodium borohydride.

Oxidation of the monoreduced bisadduct in the final step of thefour-step process with an oxidizing agent in an organic solvent providesthe desired unsymmetrical bisanil dye accompanied, in some cases, by thecolorless isomeric 2,3-dicyanoimidazole as shown in the aforesaidequations. The oxidation proceeds readily in tetrahydrofuran,acetonitrile, benzene, ethyl "Cellosolve" and acetone. However, in thesesolvents a large amount of imidazole is usually formed. Preferredsolvents which give the bisanil dye and little or none of the isomericimidazole are dimethylformamide, dimethylacetamide, dimethylsulfoxide,hexamethylphosphoramide and N-methylpyrrolidone. Oxidation at room(ambient) temperature (25°-30°C.) is preferred over elevatedtemperatures. Oxidizing agents that can be used include the nickeloxides, MnO₂, PbO₂, I₂, NO₂, dichlorodicyanoquinone and chloranil.Manganese dioxide gives the best yield and purity of dye and ispreferred. In particular, carrying out the reaction with manganesedioxide in dimethylformamide at 25°-30°C. for about 4 hours provides an80% yield of bisanil dye and the dye is completely free of the isomericimidazole. The bisanil dyestuff can be conveniently isolated by addingtetrahydrofuran to the reaction mixture and filtering to removeinsoluble manganese oxides, after which isopropanol is added to thefiltrate and the precipitated solids are filtered off and washed withisopropanol; the precipitate is the desired bisanil dye.

Alternatively, in order to eliminate tetrahydrofuran from the aboveprocedure, the reaction mass (after oxidation) is poured into water and,after acidification, hydrogen peroxide or sulfur dioxide is addedthereto to dissolve the manganese oxides. The resultant mixture is thenfiltered and the crude dye thus obtained is washed thoroughly withisopropanol. The latter modification eliminates both the expensivetetrahydrofuran solvent and the tedious removal of the insolublemanganese salts, thus providing for a more economical process.

The geometry about the central carbon-carbon double bond of the bisanilprepared by the four-step process is exclusively trans as evidenced bymeasurement of the dipole moment. Thus, the preferred four-step processaffords a high yield, for example, 70-80% overall fromdiaminomaleonitrile, of unsymmetrical trans-bisanil dyes uncontaminatedwith the cis isomer or the isomeric imidazole.

The symmetrical bisanil dyes previously discussed can also be preparedby the aforesaid four-step process but they are more advantageouslyprepared in good yield by the one-step process previously described.

As still another example of a process which can be employed herein is atwo-step process by which can be prepared symmetrical or unsymmetricalbisanil dyes, and particularly such dyes which have a predominantlytrans configuration. This process comprises heating diaminomaleonitrilein dimethylformamide under acidic conditions, preferably provided bysulfuric acid, with a molar equivalent of a first aryl aldehyde Ar₁ CHOto produce a monanil and then, employing the monoanil thus produced inplace of diaminomaleonitrile, repeating the procedure with a molarequivalent of either the first aryl aldehyde Ar₁ CHO or a second arylaldehyde Ar₂ CHO that is different from the first aryl aldehyde toproduce either the symmetrical or unsymmetrical bisanil dye. Thereaction times are very short, usually 10-30 minutes, and water producedduring the condensations need not be removed to facilitate formation ofthe desired product. Although dimethylformamide is the preferred aproticsolvent, other solvents are useful, for example, dimethylacetamide,hexamethylphosphoramide, dimethylsulfoxide and N-methylpryrrolidone. Thecondensations are carried out in a temperature range of 140°C. to theboiling point of the solvent. The preferred range is 140°-150°C. Acidiccatalysts, other than sulfuric acid, which are useful in providingacidic conditions include hydrochloric acid, p-toluenesulfonic acid andtrifluoroacetic acid.

Preferred symmetrical bisanil dyes herein include: ##SPC5##

Preferred unsymmetrical bisanil dyes herein include: ##SPC6##

The crude wet dye from any of the above processes is convenientlyconverted into a commercially usable form by mixing the crude dye, forexample, ten parts on a 100% basis, with about 2.5 parts of a ligninsulfonate dispersant and water in a colloid or sand mill. Milling iscontinued until a fine, stable aqueous dispersion or paste is obtained,that is, until dye particle size is reduced to approximately one micron(average size).

Both the symmetrical and unsymmetrical bisanil dyes possess hightinctorial strengths and provide, on polyester, extremely bright,fluorescent yellow to blue dyeings having generally good fastness tosublimation and moderate fastness to light. These dyes are especiallyuseful for dyeing and printing polyester where bright shades aredesired. Because of the chemical versatility inherent in the perparativemethods disclosed herein and because of the very high tinctorialstrengths and breadth of shades obtainable, the bisanil dyes can be usedin such a way as to suppress very undesirable coloration featureswithout paying a color value penalty.

The bisanil dye can be applied to polyester fibers, either alone or incellulosic blends, by an aqueous procedure, preferably under pressure,or by padding the fibers with an aqueous dispersion of the dye followedby dry heat (for example, Thermosol) fixation. Such dyeing proceduresare widely used in the trade. The bisanil dyes are also useful fordyeing and printing polyester fibers, and their cellulosic blends,preferably employing a fabric which subsequently receives a durablepress treatment.

The following experiments typify the aforementioned aqueous andThermosol dyeing procedures.

Experiment 1 -- Aqueous (Pressure) Dyeing Procedure

Five grams of commercially available polyester fabric were placed in anautoclave containing:

    an aqueous dye paste (15% active ingredient)                                  containing the dye of Example 4                                                                        0.1 gram                                             an anionic long chain sodium hydrocarbon                                      sulfonate (10% solution) 1.0 ml.                                              a nonionic long chain alcohol-ethylene oxide                                  adduct (10% solution)    0.5 ml.                                              ethylenediaminetetraacetic acid, sodium salt                                  (1% solution)            1.25 ml.                                             butyl benzoate carrier (10% solution)                                                                  1.5 ml.                                              water                    to 75 ml.                                            acetic acid              to adjust the                                                                 pH to 5.5.                                       

The contents of the autoclave were heated for 1 hour at 265°C. The dyedfabric was then rinsed in water and dried. The polyester fabric was dyedan extremely bright, fluorescent red shade.

Experiment 2 -- Thermosol Procedure

A pad bath was prepared containing:

    an aqueous dye paste (15% active ingredient)                                  containing the dye of Example 5                                                                        50 grams                                             purified natural gum thickener                                                                         20 grams                                             water                    to 1 liter.                                      

The pad bath was padded on commercially available 65/35 polyester/cottonfabric with a pickup of 50-65%, based on dry fabric weight (owf),followed by drying (infrared predrying followed by hot air or hot candrying is preferable) to remove the water. Thermosoling, by which thepolyester component was dyed with the disperse dye, was accomplished byheating the dried pigment-padded fabric for 90 seconds at 213°C. Unfixedsurface dye, on either the polyester or the cotton or both, was removedby padding the fabric from an aqueous bath containing 50 g./l. of sodiumhydroxide and 40 g./l. of sodium hydrosulfite at 27°-39°C., followed bysteaming for 30 seconds. The fabric was then rinsed in water at 27°C.,scoured for 5 minutes at 93°C. in water containing 1% ether alcoholsulfate detergent, rinsed in water at 27°C. and then dried. After dyeingand cleaning, the material was then padded (for permanent presstreatment) with a pickup of 50-65% (owf) with a bath containing:

                               g./l.                                              a dimethyloldihydroxyethyleneurea cross-linking                               agent                      200.0                                              a p-octylphenoxy(C.sub.2 H.sub.4 O).sub.9-10 H wetting agent                                             2.5                                                a dispersed acrylic thermoplastic binding agent                                                          22.5                                               a nonionic, paraffin-free, polyethylene emulsion                              which serves as a fabric softener                                                                        22.5                                               a nonionic polymer emulsion which imparts luster,                             a silky hand and antistatic properties to the                                 fiber                      30.0                                               a 20% aqueous zinc nitrate curing catalyst                                                               36.0.                                          

The resin-impregnated material was air dried to remove the water andthen cured at 163°C. for 15 minutes. The durable-press treatedpolyester/cotton fabric was dyed an attractive, bright, fluorescentscarlet shade.

The following examples are given to illustrate the preparation of thebisanil dyes described above. All parts are given by weight unlessotherwise noted.

EXAMPLE 1 Preparation of Symmetrical Bisanil

A mixture of 2.16 parts of diaminomaleonitrile, 9.16 parts of4-[N,N-bis(cyanoethyl)amino]benzaldehyde, 0.2 part of p-toluenesulfonicacid, 30 parts of dimethylacetamide (DMAC) and 150 parts of benzene washeated at 80°-90°C. while benzene plus water was removed bydistillation. After distillation for 17 hours, the remaining benzene wasremoved by distillation under nitrogen. After cooling the DMAC solutionto -5°C. 4.2 parts of red bisanil were collected by filtration; its m.p.was 218°-220°C. Thin layer chromatography on silica gel-coated glassplates using benzene-acetonitrile (4:1) as eluent showed one scarletspot at an R_(f) of < 0.1. Calc'd. for C₃₀ H₂₆ N₁₀ : C, 68.6; H, 5.0; N,26.5%. Found: C, 68.2; H, 5.4; N, 26.5%. An infrared spectrum of a Nujolmull of the product showed no N-H absorption at 2.8-3.1 μ. Based on theabove, the product was of the structure

p--(NCH₄ C₂)₂ N--C₆ H₄ --CH=N--C(CN)=C(CN)--N=CH--C₆ H₄ --p--N(C₂ H₄CN)₂.

the mother liquor from the aforesaid filtration was poured into a largevolume of ice-cooled water and the precipitated solids were isolated byfiltration, washed with water and dried to give 3.9 parts of a redsolid, m.p. 185°-186°C. Thin layer chromatography showed the presence ofa minor scarlet spot at an R_(f) of < 0.1 and a major yellow spot at anR_(f) of 0.6. The product showed absorption bands at 515 mμ (a_(max). of10 liters g.⁻ ¹ cm.⁻ ¹) for the bisanil and at 410 mμ (a_(max). of 87liters g.⁻ ¹ cm.⁻ ¹) for the monoanil formed by hydrolysis of thebisanil during the DMF treatment. Calc'd. for C₃₀ H₂₆ N₁₀ : C, 68.6; H,5.0; N, 26.5%. Found: C, 67.0; H, 5.7; N, 29.5%. Thus, hydrolysis of thebisanil occurred to provide a mixture comprising a preponderance of themonoanil and a minor amount of the bisanil.

EXAMPLE 2 Preparation of Symmetrical Bisanil

A mixture of 3.24 parts of diaminomaleonitrile, 10.6 parts of4-[N,N-bis(ethyl)amino]benzaldehyde and 50 parts of glacial acetic acidwas stirred at 115°-120°C. for 4 hours. After standing at 25°-30°C. for18 hours, the solids were collected, washed with 25 parts of cold aceticacid, then with two 25-part portions of isopropanol and dried to give5.3 parts (60.8% yield) of the symmetrical bisanil dye as dark bluemetallic flakes, m.p. 268°-270°C. The dye had an absorptivity (a_(max).)of 265 liters g..sup. ⁻¹ cm..sup.⁻¹ at a wavelength (λ_(max).) of 561mμ. Based on the above, the dye was of the structure

    p--(H.sub.5 C.sub.2).sub.2 N--C.sub.6 H.sub.4 --CH=N--C(CN)=C(CN)--N=CH--C.sub.6 H.sub.4 --p--N(C.sub.2 H.sub.5).sub.2.

a similar result was obtained by starting with the appropriate monoanilderivative instead of diaminomaleonitrile.

EXAMPLE 3 Preparation of Unsymmetrical Bisanil by a Two-Step Process

a. A mixture of 132 parts of diaminomaleonitrile, 210 parts of4-[N,N-bis(ethyl)amino]benzaldehyde, 30 drops of concentrated sulfuricacid and 2,000 parts of tetrahydrofuran (THF) was heated at 65°C. for 3hours. The tetrahydrofuran was partially evaporated and 1,000 parts ofethanol were added. The precipitated solids were isolated by filtrationand air dried to give 227 parts of yellow monoanil (76% yield). Amixture of 14.1 parts of 4-chlorobenzaldehyde, 20 drops of piperidineand 500 parts of benzene was heated at 80°-90°C. while continuouslyazeotroping the water formed during the reaction. The monoanil (13.4parts) was then added in portions over a 6-hour period and heating at80°-90°C. was continued for an additional 2 hours. The solvent wasremoved by distillation and the resultant solid residue was boiled with200 parts of isopropanol. After filtration and drying, 9.2 parts (47%yield) of red product were obtained, m.p. 207°-208°C. Thin layerchromatography showed the major component to be the unsymmetrical dyealong with small amounts of purple impurities. The dye had anabsorptivity (a_(max).) of 177 liters g..sup.⁻¹ cm..sup.⁻¹ at awavelength (λ_(max).) of 528 mμ. Cal'd. for C₂₂ H₂₀ N₅ Cl: C, 67.8; H,5.2; N, 18.0%. Found: C, 68.6; H, 5.6; N, 17.9%. Based on the above, thedye was of the structure

    p--Cl--C.sub.6 H.sub.4 --CH=N--C(CN)=C(CN)--N=CH--C.sub.6 H.sub.4 --p--N(C.sub.2 H.sub.5).sub.2.

b. A mixture of 6.7 parts of the monoanil of part (a), 7.05 parts of4-chlorobenzaldehyde, 0.85 part of piperidine and 250 parts of benzenewas heated at 80°-90°C. for 1 hour continuously azeotroping the waterformed during the reaction. Thin layer chromatography of the reactionmixture showed the presence of approximately equal amounts of thetrans-symmetrical and -unsymmetrical bisanil dyes; only traces ofcis-bisanil dyes could be detected.

c. When the condensation was run on the same scale but in the presenceof only 1 drop of piperidine, the major products after 1 hour at80°-90°C. were the cis-symmetrical and -unsymmetrical bisanil dyes. Onlytraces of trans-bisanil dyes were present.

EXAMPLE 4 Preparation of Unsymmetrical Bisanil by a Four-Step Process

A mixture of 21.6 parts of diaminomaleonitrile, 38.3 parts of4-bromobenzaldehyde, 5 drops of concentrated sulfuric acid and 250 partsof tetrahydrofuran was stirred at 25°-30°C. for 4 hours. Methanol (100parts) was added and 7.95 parts of sodium borohydride were added inportions over a 20-minute period while maintaining the temperature at20°-25°C. by external cooling in ice water. After stirring for 15minutes at 20°-25°C. most of the solvent was removed by distillation.The remaining solution was poured into 1,500 parts of ice-cooled waterand stirred for 1 hour; the resultant solids were collected and airdried to give 53.5 parts (97% yield) of the reduced monoadduct. Thismaterial was used in the next step of the reaction sequence withoutpurification.

A slurry of 53 parts of the reduced monoadduct, 38.8 parts of4-[N,N-bis(ethyl)amino]benzaldehyde, 1.2 parts of concentrated sulfuricacid and 1,000 parts of ethanol was stirred for 4 hours at 25°-30°C. Thereaction mixture was filtered and collected solids were air dried,yielding 83 parts (99% yield) of orange reduced bisadduct. This productwas of sufficient purity to use in the next reaction withoutpurification.

A mixture of 82 parts of the reduced bisadduct, 75 parts of manganesedioxide and 500 parts of dimethylformamide was stirred for 4 hours at25°-30°C. Tetrahydrofuran (500 parts) was added and the resultingmixture was filtered through a medium porosity, sintered glass funnel.The solids thus obtained were washed with four 400-part portions oftetrahydrofuran to dissolve and separate the precipitated bisanil dyefrom the insoluble manganese oxides. The combined tetrahydrofuranfiltrates were concentrated under reduced pressure to a thick slush; 600parts of isopropanol were added and the resultant slurry was filtered;the collected solids were washed with three 100-part portions ofisopropanol to give 61.5 parts (75.6% yield) of bisanil dye, as metallicgreen flakes, exhibiting an absorptivity (a_(max).) of 153 litersg..sup.⁻¹ cm..sup.⁻¹ at a wavelength (λ_(max).) of 531 mμ.Recrystallization of the product from benzene gave very dark needles,m.p. 205°-206°C.; it exhibited an a_(max). of 166 liters g..sup.⁻¹cm..sup.⁻¹ at a λ_(max). of 531 mμ. Calc'd. for C₂₂ H₂₀ N₅ Br: C, 60.8;H, 4.7; N, 16.1%. Found: C, 59.5; H, 4.8; N, 15.6%. Thin layerchromatographic analysis of the product showed only a single purplespot. Based on the above, the dye was of the structure

    p--Br--C.sub.6 H.sub.4 --CH=N--C(CN)=C(CN)--N=CH--C.sub.6 H.sub.4 --p--N(C.sub.2 H.sub.5).sub.2.

example 5 preparation of Unsymmetrical Bisanil by a Four-Step Process

A mixture of 10.8 parts of diaminomaleonitrile, 15.6 parts of1-naphthaldehyde, 5 drops of concentrated sulfuric acid and 125 parts oftetrahydrofuran was stirred at 25°-30°C. for 17 hours. Methanol (35parts) was added and the solution was cooled to 15°C. Sodium borohydride(3.8 parts) was added in portions while maintaining the temperaturebetween 15°-20°C. by external water-ice cooling. After stirring for 15minutes, the solution was poured into 1,500 parts of ice-cooled waterand stirred for 3 hours; the solids (the reduced monoadduct as a lighttan powder) were removed by filtration.

A slurry of the reduced monoadduct, 18 parts of4-[N,N-bis(ethyl)amino]benzaldehyde, 15 drops of concentrated sulfuricacid and 200 parts of ethanol was stirred for 17 hours at 25°-30°C. Thesolids were isolated by filtration, yielding 35.4 parts of the reducedbisadduct as an orange powder.

A mixture of the reduced bisadduct, 35 parts of manganese dioxide and150 parts of dimethylformamide was stirred for 5 hours at 25°-30°C. Thesolids were isolated by filtration and washed with four 400-partportions of tetrahydrofuran to give a solution of the desired bisanildye. The tetrahydrofuran and dimethylformamide were distilled off underreduced pressure and the solids thus obtained were washed withisopropanol and dried, yielding 32.5 parts (80% yield) of bisanil dye asa dark red powder, m.p. 211°-213°C.; it exhibited an absorptivity(a_(max).) of 183 liters g..sup.⁻¹ cm..sup.⁻¹ at a wavelength (λ_(max).)of 540 mμ. Calc'd. for C₂₆ H₂₃ N₅ : C, 77.0; H, 5.7; N, 17.3%. Found: C,76.3; H, 5.6; N, 17.4%. Thin layer chromatography showed only a singlepurple spot. Based on the above, the dye was of the structure ##SPC7##

EXAMPLE 6 Preparation of Unsymmetrical Bisanil by a Four-Step Process

Example 5 was substantially repeated except that another solvent wasused in place of tetrahydrofuran in both the reduction and oxidationsteps. To a slurry of 12.7 parts of the monoanil of Example 5 in 50parts of ethyl "Cellosolve" was added in portions, 0.95 part of sodiumborohydride while maintaining the temperature at 25°-35°C. by externalcooling in ice-cooled water. The resulting solution was stirred for 30minutes, poured into 500 parts of ice water and stirred for 1 additionalhour. The light tan precipitate was collected by filtration and airdried to give 12.4 parts (100% yield) of reduced monoadduct.

The reduced monoadduct was condensed with4-[N,N-bis(ethyl)amino]benzaldehyde in ethanol as described in Example 5to yield the reduced bisadduct.

A mixture of 5.0 parts of the reduced bisadduct, 5.0 parts of manganesedioxide and 35 parts of dimethylformamide was stirred for 2 hours at25°-30°C. The solution was poured into 350 parts of ice-cooled water and9 parts of concentrated sulfuric acid were added. Hydrogen peroxide (6parts of a 30% aqueous solution) was added in portions to dissolve themanganese oxides. The resulting mixture was filtered and the crude dyethus obtained was washed with two 50-part portions of isopropanol anddried to give 4.5 parts (89.4% yield) of the bisanil dye, as a redsolid, exhibiting an absorptivity (a_(max).) of 169 liters g..sup.⁻¹cm..sup.⁻¹ at a wavelength (λ_(max).) of 540 mμ. Thin layerchromatography showed only a single purple spot; the R_(f) was identicalto that of the dye of Example 5.

EXAMPLE 7 Preparation of Unsymmetrical Bisanil by a Four-Step Process

The dye of Example 5 was also prepared by reaction of the reducedbisadduct (9.6 parts) with 10.6 parts of lead dioxide (0.04 mole) in 200parts of acetonitrile at 50°-55°C. for 9 hours. The suspended leadsludge was filtered off and the solvent was evaporated. Thin layerchromatography showed the residue to consist of approximately equalamounts of the unsymmetrical bisanil dye of Example 4 and the colorlessisomeric imidazole. The imidazole was removed by prolonged extraction ofthe solid with hot (80°-90°C.) ethanol; the extracted product was shownby thin layer chromatography to consist of a single purple spot. Theanalytical data obtained on the product was substantially the same asthat reported in Example 4.

EXAMPLE 8 Preparation of Symmetrical Bisanil

A mixture of 9.4 parts of 4-[N,N-bis(ethyl)amino]benzaldehyde, 2.16parts of diaminomaleonitrile, 4.0 parts of phosphorus pentoxide, 6 dropsof concentrated sulfuric acid and 70 parts of hexamethylphosphoramidewas stirred at 50°-55°C. for 6 hours. After each 2-hour period, anadditional 1.0 part of phosphorus pentoxide was added. The reactionmixture was then poured into 800 parts of water containing 20 parts ofaqueous ammonium hydroxide. After stirring for 1 hour, the precipitatedsolids were collected by filtration, washed with water and dried toyield 5.5 parts (65% yield) of symmetrical bluish-red bisanil, m.p.140°-142°C. The product was recrystallized three times from isopropanol,providing an analytically pure sample, m.p. 162°-165°C. The productexhibited a high intensity absorption band (105 liters g..sup.⁻¹cm..sup.⁻¹) at a wavelength of 558 mμ and, in addition, two lowerintensity bands at 400 mμ (61.5 liters g..sup.⁻¹ cm..sup.⁻¹) and 382 mμ(56 liters g..sup.⁻¹ cm..sup.⁻¹). Based on the presence of the lowerwavelength absorption bands and the large observed dipole moment of 14.6Debye, the product was confirmed as having cis geometry about thecentral carbon-carbon double bond. Based on the above, the structure is

    p--(H.sub.5 C.sub.2).sub.2 N--C.sub.6 H.sub.4 --CH=N--C(CN)=C(CN)--N=CH--C.sub.6 H.sub.4 --p--N(C.sub.2 H.sub.5).sub.2.

example 9 preparation of Symmetrical Bisanil

A mixture of 10.8 parts of diaminomaleonitrile, 29.0 parts ofindole-3-carboxaldehyde, 400 parts of tetrahydrofuran and 10 drops ofconcentrated sulfuric acid was stirred at 65°C. for 16 hours. Thetetrahydrofuran was partially evaporated and 10 parts of 10% aqueoussodium carbonate were added. The precipitated solids were isolated byfiltration, washed with water, then with isopropanol and dried to give20.3 parts of yellow monoanil (86% yield), m.p. 227.5°-229°C.

A mixture of 14.1 parts of the monoanil, 12.0 parts of concentratedsulfuric acid, 11.6 parts of indole-3-carboxaldehyde and 150 parts ofdimethylformamide was heated in about 10 minutes to 145°-150°C.; it wasmaintained at this temperature for 20 minutes. The reaction mixture wasthen poured into 1,000 parts of water. The precipitated solids werecollected by filtration, washed with water, then with isopropanol anddried. The product was recrystallized three times fromacetonitrile-chloroform to give 6.85 parts (31.7% yield) of thesymmetrical yellow bisanil, m.p. 331°-333°C. The dye had an absorptivity(a_(max).) of 220 liters g..sup.⁻¹ cm..sup.⁻¹ at a wavelength (λ_(max).)of 480 mμ. Calc'd. for C₂₂ H₁₄ N₆ : C, 72.9; H, 3.9; N, 23.2%. Found: C,71.4; H, 4.3; N, 22.3%. Based on the above, the structure of the dye is##SPC8##

EXAMPLE 10 Preparation of Unsymmetrical Bisanil

A mixture of 4.7 parts of indole-3-carboxaldehydediaminomaleonitrilemonoanil, 3.54 parts of 4-[N,N-bis(ethyl)amino]benzaldehyde, 4.0 partsof concentrated sulfuric acid and 50 parts of dimethylformamide washeated at 145°-150°C. for 20 minutes. The reaction mixture was thenpoured into 1,000 parts of water. The precipitated solids were filteredoff, washed with water and dried. Thin layer chromatographic analysisshowed the presence of the two possible symmetrical bisanil condensates,together with a third bright reddish-orange component. The lattermaterial was isolated from the product mixture by column chromatographyon "Florisil" using chlororform as eluent. After two recrystallizationsfrom acetonitrile, a small amount (0.10 part) of the pure unsymmetricalbisanil condensate was obtained, m.p. 265°-268°C. Infrared analysisshowed an NH band at 3395 cm..sup.⁻¹ and CN absorption at 2200cm..sup.⁻¹ and 660 cm..sup.⁻¹. The visible absorption spectrum exhibiteda λ_(max). of 522 mμ and an a_(max). of 239 liters g..sup.⁻¹ cm..sup.⁻¹.Based on the above, the structure of the dye is ##SPC9##

EXAMPLE 11 Preparation of Symmetrical Bisanil

A mixture of 2.16 parts of diaminomaleonitrile, 3.5 parts of4-[N,N-bis(ethyl)amino]benzaldehyde, 8.0 parts of concentrated sulfuricacid and 50 parts of dimethylformamide was stirred at 145°-150°C. for 20minutes. The reaction mixture was then poured into 1,000 parts of water;the precipitated solids were collected by filtration, washed with waterand dried. The product was purified by column chromatography on"Florisil" using chloroform as eluent, yielding 0.47 part of bluish-redbisanil, m.p. 265°-268°C. It exhibited an absorptivity (a_(max).) of 265liters g..sup.⁻¹ cm.sup.⁻¹ at a wavelength of 561 mμ. A nuclear magneticresonance (NMR) spectrum of the product was found to be identical tothat of the dye of Example 8. However, the absence of any lowerwavelength absorption, together with the much higher melting point and alow observed dipole moment of 3.2 Debye indicates that the product isactually the trans form of the dye of Example 8.

The isomerization of the cis dye of Example 8 to the trans form of thisexample was readily effected by heating the former dye in benzenecontaining a small amount of iodine. The resultant product was identicalin m.p. and spectral properties to the trans isomer.

EXAMPLES 12-118

Symmetrical bisanil dyes were prepared (Examples 12-19) by proceduressimilar to that described in Example 2. Unsymmetrical bisanil dyes wereprepared (Examples 20-118) by preferred four-step process similar tothose described in Examples 4 and 5. Data for the dyes produced areshown in Table II. Except as noted below the substituents A, B, C, X, Yand Z appearing as column headings in the table correspond to thesubstituents shown in the formula ##SPC10##

The groups shown in column Y for Examples 34, 39, 82, 87, 88 and 95correspond to the entire group ##SPC11##

Similarly, the groups shown in column B for Examples 27, 31, 49, 50, 52,53, 55, 61, 62, 64, 65, 66, 70, 78-83, 89-99 and 118 correspond to theentire group ##SPC12##

                                      TABLE II                                    __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    12    H       H          H       H      H                 H                   13    H       (4')-N(n-  H       H      (4)-N(n-C.sub.3 H.sub.7).sub.2                                                                  H                                 C.sub.3 H.sub.7).sub.2                                          14    H       (4')-OCH.sub.3                                                                           H       H      (4)-OCH.sub.3     H                   15    (2')-OCH.sub.3                                                                        (4')-OCH.sub.3                                                                           H       (2)-OCH.sub.3                                                                        (4)-OCH.sub.3     H                   16    H       (4')-N(C.sub.2 H.sub.5)-                                                                 H       H      (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                                 C.sub.2 H.sub.4 CN                                              17    (2')-CH.sub.3                                                                         (4')-N(C.sub.2 H.sub.5)-                                                                 H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                                 C.sub.2 H.sub.4 CN                                              18    (2')-Cl (4')-N(CH.sub.3).sub.2                                                                   H       (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   19    H       (4')-N(CH.sub.3)-                                                                        H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 --       H                                 C.sub.2 H.sub.4 CO.sub.2 CH.sub.3                                                                        CH.sub.3                             20    H       H          H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                                  HN                  21    H       (4')-Cl    H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                                  HN                  __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       a max.   Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    12    432   --       Yellow   58.4 7.4   34.2 57.9  6.8  34.5                 13    561   205      Bluish   74.5 7.9   17.6 73.6  7.2  17.7                                      Red                                                      14    427   159      Greenish 69.8 4.7   16.3 69.3  4.8  15.1                                      Yellow                                                   15    460   170      Yellow   --   --    --   --    --   --                   16    540   215      Red      70.6 5.9   23.5 70.2  6.0  22.6                 17    550   171      Bluish   71.4 6.4   22.5 71.7  6.7  21.9                                      Red                                                      18    555   223      Bluish   60.2 4.6   19.1 60.3  4.7  19.5                                      Red                                                      19    543   194      Red      65.4 5.9   16.3 64.2  5.4  16.0                 20    500   141      Bright   72.1 4.9   22.9 72.0  4.9  22.9                                      Orange                                                   21    510   168      Orange   65.9 4.2   21.0 64.7  4.1  21.2                 __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    22    (2')-Cl H          (6')-Cl H      (4)-N(CH.sub.3)C.sub. 2 H.sub.4                                               CN                H                   23    (2')-NO.sub.2                                                                         H          H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                                  HN                  24    H       (4')-NO.sub.2                                                                            H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                                  HN                  25    H       H          H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   26    H       H          H       (2)-OH (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   27    --      2-furyl    --      H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   28    (2')-OH H          H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   29    H       H          H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                   30    H       H          H       H      (4)-N(C.sub.2 H.sub.4 CN).sub.2                                                                 H                   31    --      2-furyl    --      H      (4)-N(C.sub.2 H.sub.4 CN)C.sub.2                                              H.sub.4 --        H                                                           OCOC.sub.6 H.sub.5                    __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1                                                      Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    22    514   135      Orange   60.6 3.7   19.3 61.0  3.6  18.9                 23    512   115      Orange   64.1 4.1   23.8 63.5  4.0  22.7                 24    530   135      Bright   64.2 4.2   23.8 63.4  4.4  22.3                                      Red                                                      25    525   195      Red      74.3 6.0   19.7 74.5  6.2  19.5                 26    527   176      Bright   71.2 5.7   18.8 66.8  5.2  17.1                                      Red                                                      27    530   208      Red      69.6 5.5   20.3 68.5  5.1  19.6                 28    531   186      Bright   71.1 5.7   19.0 67.8  6.2  17.6                                      Red                                                      29    510   138      Bright   73.1 5.6   21.3 69.9  5.0  19.9                                      Orange                                                   30    488   152      Yellow   71.0 4.7   24.3 72.5  4.7  24.2                 31    500   118      Orange   68.5 4.5   17.1 67.8  4.1  16.9                 __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    32    (2')-NO.sub.2                                                                         H          H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   33    (2')-Cl H          (6')-Cl H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   34    H       H          H       --     4-N,N-dimethyl-   --                                                          amino-1-naphthyl                      35    H       (4')-NO.sub.2                                                                            H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   36    H       H          H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)CH.sub.2                                                CH--              H                                                            CH.sub.2 OC.sub.6 H.sub.5                                                    |                                                                    OCONHC.sub.6 H.sub. 5                 37    H       (4')-Cl    H       H      (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 --        H                                                           OCOC.sub.6 H.sub.5                    38    (2')-Cl H          H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   39    (2')-Cl H          (6')-Cl --     3-indolyl         --                  40    H       (3')-Cl    H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                   41    H       (4')-Cl    H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                   __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1                                                      Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    32    542   150      Violet   66.0 5.1   21.0 64.4  5.2  20.5                 33    540   145      Bright   62.3 4.5   16.5 61.5  4.7  15.7                                      Bluish Red                                               34    560   133      Bluish   76.4 5.1   18.6 74.6  5.8  19.3                                      Red                                                      35    560   118      Violet   66.0 5.0   21.0 66.9  5.7  17.8                 36    520    92      Bright   72.8 5.6   13.8 69.0  5.9  11.7                                      Orange                                                   37    520   107      Bright   68.1 4.7   13.7 67.9  4.6  12.9                                      Orange                                                   38    540   124      Bright   67.8 5.2   18.0 67.2  5.0  17.3                                      Bluish Red                                               39    460   121      Reddish  61.3 2.8   17.8 59.8  2.7  18.5                                      Yellow                                                   40    523   154      Bright   67.2 6.0   19.6 67.3  5.2  19.2                                      Orange                                                   41    520   153      Bright   67.2 6.0   19.6 67.2  5.1  19.4                                      Orange                                                   __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    42    H       (3')-Cl    H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   43    (2')-Cl H          H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   44    H       H          H       (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   45    H       (4')-Cl    H       (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   46    (3')-Cl (4')-Cl    H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   47    (3')-Cl (4')-Cl    H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                   48    (2')-Cl (6')-NO.sub.2                                                                            H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   49    --      1-naphthyl --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                   50    --      1-naphthyl --      H      (4)-N(CH.sub.2 CH.sub.2 CH.sub.2                                              CH.sub.3 ).sub.2  H                   __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    42    533   152      Bright   67.8 5.2   18.0 68.0  5.3  17.4                                      Red                                                      43    540   118      Bright   67.8 5.2   18.0 68.0  5.5  17.4                                      Red                                                      44    510   145      Orange   66.4 4.5   19.3 64.7  5.1  17.1                 45    519   148      Orange   61.1 3.8   17.6 61.2  5.4  12.1                 46    540   157      Bright   62.2 4.5   16.5 60.7  4.6  15.6                                      Bluish Red                                               47    518   162      Scarlet  --   --    --   --    --   --                   48    550   139      Violet   60.8 4.4   19.3 60.9  4.4  19.1                 49    527   158      Scarlet  75.4 5.4   18.9 76.2  5.8  17.8                 50    540   146      Red      78.1 6.8   15.2 77.7  6.7  14.8                 __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    51    (2')-Cl H          (6')-Cl (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   52    --      1-naphthyl --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   53    --      1-naphthyl --      H      (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 --        H                                                            OCOC.sub.6 H.sub.5                   54    (2')-Cl H          (6')-Cl H      (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 --        H                                                            OCOC.sub.6 H.sub.5                   55    --      2-quinolinyl                                                                             --      H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   56    H       (3')-CN    H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    51    545   138      Violet   63.0 4.8   15.9 58.5  4.9  15.8                 52    545   170      Bright   77.3 6.0   16.7 77.3  6.1  16.6                                      Bluish Red                                               53    527   138      Scarlet  75.5 5.2   13.3 75.0  5.3  13.1                 54    527   115      Scarlet  64.0 4.3   12.9 63.8  4.4  12.8                 55    551   198      Bright   74.9 5.5   20.7 74.4  5.5  20.8                                      Bluish Red                                               56    535   167      Bright   72.6 5.3   22.1 73.0  5.6  22.3                                      Bluish Red                                               __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    57    (2')-NO.sub.2                                                                         (4')-NO.sub.2                                                                            H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   58    (3')-Br (4')-OCH.sub.3                                                                           (5')-OCH.sub.3                                                                        H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   59    (2')-OH (3')-Br    (5')-Br H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   60    (3')-Cl (4')-Cl    H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   61    --      2-thienyl  --      H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   62    --      2-hydroxy-1-                                                                             --      H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                                 naphthyl                                                        63    (2')-F  H          H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    57    590   110      Blue     60.1 4.6   21.3 60.5  4.7  20.3                 58    532   145      Bright   58.3 4.9   14.2 59.3  5.0  14.3                                      Scarlet                                                  59    560   107      Bright   50.0 3.6   13.2 49.9  3.7  12.9                                      Violet                                                   60    545   171      Bright   63.0 4.8   16.0 63.1  4.8  16.1                                      Bluish Red                                               61    532   192      Bright   --   --    --   --    --   --                                        Red                                                      62    550   196      Violet   73.8 6.0   16.5 75.1  5.4  17.1                 63    532   186      Bright   70.8 5.4   18.7 71.0  5.1  18.8                                      Red                                                      __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    64    --      1-naphthyl --      (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   65    --      2-hydroxy-1-                                                                             --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                                 naphthyl                                                        66    --      1-naphthyl --      (2)-CH.sub.3                                                                         (4)-N(CH.sub.2 CH.sub.2 CH.sub.2                                              CH.sub.3).sub.2   H                   67    (3')-Cl (4')-Cl    H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   68    (3')-Cl (4')-Cl    H       (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   69    H       (4')-OCH.sub.3                                                                           H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   70    --      1-naphthyl --      (2)-CH.sub.3                                                                         (4)-N(CH.sub.3).sub.2                                                                           (6)-CH.sub.3        __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g.sup.-.sup.1 cm..sup.-.sup.1)                                                      Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    64    520   163      Orange   70.0 4.4   17.0 68.4  4.3  16.8                 65    559   178      Violet   74.5 5.8   16.1 73.9  5.5  16.3                 66    547   158      Bluish   78.3 7.0   14.7 77.8  6.7  14.9                                      Red                                                      67    521   152      Bright   61.0 3.9   14.2 58.7  4.2  14.9                                      Red                                                      68    520   150      Bright   55.8 3.3   16.3 55.4  3.5  16.1                                      Coral                                                    69    523   208      Bright   --   --    --   --    --   --                                        Scarlet                                                  70    540   175      Bluish   --   --    --   --    --   --                                        Red                                                      __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    71    (2')-CH(CH.sub.3).sub.2                                                               (4')-Br    (5')-CH(CH.sub.3).sub.2                                                               (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CN        H                   72    H       (4')-Br    H       (2)-CH.sub. 3                                                                        (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   73    H       (4')-Br    H       H      (4)-N(CH.sub.2 CH.sub.2 CH.sub.2                                              CH.sub.3).sub.2   H                   74    (2')-CH(CH.sub.3).sub.2                                                               (4')-Br    (5')-CH(CH.sub.3).sub.2                                                               (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   75    (2')-CH(CH.sub.3).sub.2                                                               (4')-Br    (5')-CH(CH.sub.3).sub.2                                                               H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   76    --      2-thienyl  --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   77    H       (4')-OCH.sub.3                                                                           H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   78    --      4,5-dibromo-2-thienyl                                                                    --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   79    --      4,5-dibromo-2-thienyl                                                                    --      H      (4)-N(CH.sub.2 CH.sub.2 CH.sub.3).                                            sub.2             H                   80    --      4,5-dibromo-2-thienyl                                                                    --      H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   81    --      4,5-dibromo-2-thienyl                                                                    --      H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   82    --      4,5-dibromo-2-thienyl                                                                    --      --     5-diethylamino-2-thiazolyl                                                                      --                  83    --      4,5-dibromo-2-thienyl                                                                    --      (2)-CH.sub.3                                                                         (4)-N(CH.sub.2 CH.sub.2 CH.sub.3).                                            sub.2             H                   __________________________________________________________________________    Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    71    521   123      Scarlet  64.6 5.9   15.1 63.1  5.4  15.8                 72    540   158      Bluish-red                                                                             61.6 4.9   15.6 61.0  4.2  15.7                 73    532   161      Red      63.4 6.1   14.2 61.9  5.9  14.8                 74    542   140      Bluish-red                                                                             65.4 6.4   13.1 64.9  5.9  13.2                 75    535   145      Red      64.9 6.2   13.5 64.4  6.1  13.9                 76    535   194      Red      67.2 5.6   18.6 69.5  5.3  18.1                 77    525   192      Scarlet  72.1 6.3   17.5 73.0  6.0  17.9                 78    560   187      Bluish-red                                                                             47.3 3.6   13.1 47.4  3.8  13.7                 79    553   127      Bluish-red                                                                             48.2 3.8   12.8 48.5  3.3  12.5                 80    534   114      Red      44.8 3.0   12.4 44.1  2.8  12.7                 81    550   150      Bluish-red                                                                             46.2 3.3   13.5 46.5  2.9  13.4                 82    522   135      Scarlet  49.9 2.5   15.0 50.3  2.7  14.4                 83    558   130      Violet   49.2 4.1   12.5 49.0  3.8  12.1                 __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    84    H       (4')-OCH.sub.3                                                                           H       H      (4)-NHCOCH.sub.3  H                   85    H       (4')-OCH.sub.3                                                                           H       (2)-CH.sub.3                                                                         (4)-N(CH.sub.2 CH.sub.2 CH.sub.3).                                            sub.2             H                   86    H       (4')-OCH.sub.3                                                                           H       (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   87    H       (4')-OCH.sub.3                                                                           H       --     6-N-(methyl)-2,2,4,7-tetra-                                                                     --                                                          methyl-1,2,3,4-tetrahydro-                                                    quinolyl                              88    H       (4')-NHCOCH.sub.3                                                                        H       --     6-N-(methyl)-2,2,4,7-tetra-                                                                     --                                                          methyl-1,2,3,4-tetrahydro-                                                    quinolyl                              89    --      5-bromo-2-thienyl                                                                        --      (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   90    --      5-bromo-2-thienyl                                                                        --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   91    --      5-bromo-2-thienyl                                                                        --      H      (4)-NHCOCH.sub.3  H                   92    --      5-bromo-2-thienyl                                                                        --      H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   93    --      5-bromo-2-thienyl                                                                        --      H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   94    --      5-bromo-2-thienyl                                                                        --      (2)-CH.sub.3                                                                         (4)-N(CH.sub.2 CH.sub.2 CH.sub.3).                                            sub.2             H                   95    --      5-bromo-2-thienyl                                                                        --      --     4-diethylamino-1-naphthyl                                                                       --                  96    --      5-bromo-2-thienyl                                                                        --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CO.sub.2 CH.sub.3                                                                       H                   __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                            No.  (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    84    432   174      Yellow   67.5  5.15 18.8 63.3  4.2  17.9                 85    532   157      Scarlet  69.7 9.4   16.9 69.4  8.7  16.5                 86    508   169      Orange   78.5 4.9   19.1 77.2  4.7  19.3                 87    535   154      Bluish-red                                                                             72.5 6.8   16.9 71.8  6.2  17.4                 88    543   167      Bluish-red                                                                             71.9 6.6   18.0 73.7  6.1  18.7                 89    531   114      Red      48.4 2.9   15.7 49.3  2.4  16.1                 90    553   155      Bluish-red                                                                             55.5 4.4   15.4 55.4  4.4  16.1                 91    444   145      Yellow   50.4 3.3   16.7 50.3  2.8  16.4                 92    537   159      Bluish-red                                                                             54.6 4.2   15.9 53.8  4.1  13.5                 93    524   139      Red      52.1 3.7   14.5 51.9  3.5  14.3                 94    555   145      Bluish-red                                                                             57.3 5.0   14.5 57.4  4.2  13.9                 95    515    94      Scarlet  58.8 4.1   14.3 59.4  4.6  14.6                 96    535   138      Bluish-red                                                                             53.9 4.3   13.7 53.7  4.1  13.3                 __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    97    --      5-bromo-2-thienyl                                                                        --      (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CO.sub. 2 CH.sub.2                                                    CH.sub.2 CH.sub.2 CH.sub.3                                                                      H                   98    --      5-bromo-2-thienyl                                                                        --      (2)-CHhd 3                                                                           (4)-N(C.sub.2 H.sub.5)CH.sub.2                                                CHCH.sub.2 OC.sub.6 H.sub.5                                                                     H                                                           |                                                                    OCONHC.sub.6 H.sub.5                  99    --      1-naphthyl --      H      (4)-NHCOCH.sub.3  H                   100   (3')-Cl (4')-Cl    H       H      (4)-N(CH.sub.2 CH.sub.2 CH.sub.3).                                            sub.2             H                   101   H       (3')-NO.sub.2                                                                            H       H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   102   H       (3')-NO.sub.2                                                                            H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   103   H       (3')-NO.sub.2                                                                            H       (2)-Cl (4)-N(CH.sub.3).sub.2                                                                           H                   104   H       (3')-NO.sub.2                                                                            H       (2)-CH.sub.3                                                                         (4)-N(CH.sub.2 CH.sub.2 CH.sub.3).                                            sub.2             H                   105   H       (3')-NO.sub.2                                                                            H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CO.sub.2 CH.sub.3                                                                       H                   106   H       (3')-NO.sub.2                                                                            H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CO.sub.2 CH.sub.2                                                     CH.sub.2 CH.sub.2 CH.sub.3                                                                      H                   107   H       (3')-NO.sub.2                                                                            H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)CH.sub.2                                                CHCH.sub.2 OC.sub.6 H.sub.5                                                                     H                                                           |                                                                    OCONHC.sub.6 H.sub.5                  108   H       H          H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    97    535   110      Bluish-red                                                                             56.3 5.1   12.6 55.1  4.8  13.7                 98    534   105      Bluish-red                                                                             --   --    --   --    --   --                   99    440   116      Yellow   73.7 4.3   17.9 74.1  4.2  18.5                 100   544   138      Bluish-red                                                                             64.4 5.4   15.0 62.8  5.1  16.3                 101   534   164      Bluish-red                                                                             66.0 5.0   21.0 64.6  4.5  20.7                 102   519   128      Red      62.1 4.5   18.9 63.0  4.2  19.7                 103   518   141      Orange   59.1 3.7   20.7 58.7  4.2  23.0                 104   543   154      Bluish-red                                                                             66.4 8.0   18.6 61.2  7.1  19.7                 105   531   141      Red      63.5 5.1   17.8 63.9  5.0  17.9                 106   531   117      Red      65.4 5.8   16.3 64.1  4.9  15.8                 107   530   100      Red      75.1 5.6   16.6 77.2  4.9  15.9                 108   507   144      Orange   69.2 5.3   17.5 68.4  5.9  17.7                 __________________________________________________________________________    Example                                                                       No.   A       B          C       X      Y                 Z                   __________________________________________________________________________    109   H       (4')-NHCOCH.sub.3                                                                        H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   110   H       (4')-NHCOCH.sub.3                                                                        H       H      (4)-N(CH.sub.2 CH.sub.2 CH.sub.3).                                            sub.2             H                   111   H       (4')-NHCOC.sub.2 H.sub.5                                                                 H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   112   H       (4')-NHCOC.sub.2 H.sub.5                                                                 H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   113   H       (4')-OCH.sub.3                                                                           H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CO.sub.2 CH.sub.3                                                                       H                   114   H       (2')-Cl    H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   115   H       (2')-Cl    H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)C.sub.2                                                 H.sub.4 CO.sub.2 CH.sub.3                                                                       H                   116   H       (2')-Cl    H       (2)-CH.sub.3                                                                         (4)-N(C.sub.2 H.sub.5)CH.sub.2                                                CHCH.sub.2 OC.sub.6 H.sub.5                                                                     H                                                           |                                                                    OCONHC.sub.6 H.sub.5                  117   (3')-Cl (4')-Cl    H       H      (4)-N(CH.sub.3)C.sub.2 H.sub.4                                                CO.sub.2 CH.sub.3 H                   118   --      3-(N-methyl)indolyl                                                                      --      H      (4)-N(C.sub.2 H.sub.5).sub.2                                                                    H                   __________________________________________________________________________                                  Elemental Analysis                              Example                                                                             λ max.                                                                       .sup.a max.                                                                            Shade on Calculated      Found                           No.   (mμ)                                                                             (1.g..sup.-.sup.1 cm..sup.-.sup.1)                                                     Polyester                                                                              C    H     N    C     H    N                    __________________________________________________________________________    109   532   171      70.4     6.1  19.7  71.3 6.8   21.0                      110   527   174      Red      70.9 6.4   19.1 70.5  6.2  19.4                 111   532   139      Red      70.4 6.1   19.7 70.5  6.7  19.4                 112   510   122      Orange   66.4 5.5   17.9 66.0  5.2  17.7                 113   518   150      Scarlet  68.3 5.9   15.3 67.9  6.4  16.2                 114   520   131      Scarlet  63.9 4.4   16.2 65.2  4.5  15.8                 115   532   129      Red      65.1 5.2   15.2 64.4  4.9  16.3                 116   530    78      Red      --   --    --   --    --   --                   117   519   152      Scarlet  59.0 4.1   15.0 57.3  3.7  17.1                 118   525   215      Scarlet  73.5 5.9   20.6 70.4  5.2  19.1                 __________________________________________________________________________

I claim:
 1. One-step process of preparing the symmetrical bisanil dye ofthe formula Ar₁ CH=N--C(CN)=C(CN)--N=CH--Ar₂ wherein Ar₁ and Ar₂ are thesame and are selected from1. benzo(5- and 6-membered)heterocyclic groupscontaining 0-4 methyl substituents and
 2. 5-membered heterocyclic and6-membered heterocyclic groups containing 0-3 substituents selected fromNO₂, halogen, CN, C₁₋₄ alkyl, C₁₋₄ alkoxy, OCH₂ -phenyl, phenyl, CF₃,OH, OC₁₋₄ alkylene-N(C₁₋₄ alkyl)₂, C₂₋₄ alkylene-Cl, NHCONH₂, NHCOA,NHSO₂ A, SR₈, SO₂ R₈, NHR₁, NHCOC₁₋₄ alkylene-B and --NR₁ R₂ wherein:a.R₁ is C₁₋₄ alkyl or C₂₋₄ alkylene-R₃ ; b. R₂ is C₁₋₄ alkyl, C₂₋₄alkylene-R₄ or, if Ar₁ or Ar₂ is phenyl, C₃ alkylene attached to aphenyl position which is ortho to the position to which the nitrogen isattached; c. R₃ is CN, halogen, OH, phenyl, C₁₋₄ alkoxy, OC₁₋₄alkylene-CN, CO₂ A, OCOA, OCONHA or CO₂ C₁₋₄ alkylene-OCOA; d. R₄ is CN,halogen, OH, phenyl, OC₁₋₄ alkylene-CN, CO₂ A, OCOA, CO₂ C₁₋₄alkylene-OCOA, SO₂ A, phthalimido, succinimido, glutarimido, OCOCH=CH₂,CH₂ --CH(OCOA)CH₂ OA or CH₂ CH(OCONHA)CH₂ OA; e. A is C₁₋₄ alkyl or R₅ ;f. B is halogen, C₁₋₄ alkoxy or R₅ ; g. R₅ is phenyl containing 0-2substituents selected from C₁₋₄ alkyl, C₁₋₄ alkoxy, halogen, NO₂, CN,C₁₋₄ alkyl-CONH and NR₆ R₇ wherein each of R₆ and R₇ is independentlyselected from H and C₁₋₄ alkyl, with at least one of R₆ and R₇ beingC₁₋₄ alkyl; and h. R₈ is C₁₋₄ alkyl, C₂ H₄ OH, C₅₋₆ cycloalkyl orR₅,which process comprises heating diaminomaleonitrile and at least twomolar equivalents of the aromatic aldehyde Ar₁ CHO in the presence ofglacial acetic acid to produce the symmetrical bisanil dye of theformula AR₁ --CH = N--C(CN) = C(CN)--N = CH--Ar₂.
 2. Process of claim 1wherein the reaction is carried out at 115°-120°C. for about 4 hours andthe molar ratio of aromatic aldehyde to diaminomaleonitrile is about2:1.